I. Field
The present invention relates generally to communication, and more specifically to data transmission in a wireless communication network.
II. Background
Wireless and wireline broadcast networks are widely deployed to provide various contents to a large group of users. A common wireline broadcast network is a cable network that delivers multimedia content to a large number of households. A cable network typically includes headends and distribution nodes. Each headend receives programs from various sources, generates a separate modulated signal for each program, multiplexes the modulated signals for all of the programs onto an output signal, and sends its output signal to the distribution nodes. Each program may be distributed over a wide geographic area (e.g., an entire state) or a smaller geographic area (e.g., a city). Each distribution node covers a specific area within the wide geographic area (e.g., a community). Each distribution node receives the output signals from the headends, multiplexes the modulated signals for the programs to be distributed in its coverage area onto different frequency channels, and sends its output signal to households within its coverage area. The output signal for each distribution node typically carries both national and local programs, which are often sent on separate modulated signals that are multiplexed onto the output signal.
A wireless broadcast network transmits data over the air to wireless devices within the coverage area of the network. A wireless broadcast network is different from a wireline broadcast network in several key regards. First, signals transmitted by different base stations in the wireless broadcast network interfere with one another if these signals are not the same. In contrast, the output signal of each distribution node is sent on dedicated cables and thus experiences no interference from other distribution nodes. Second, each base station in the wireless broadcast network typically transmits a single radio frequency (RF) modulated signal that carries data for all programs being broadcast by that base station. In contrast, each distribution node in the wireline broadcast network may multiplex individual modulated signals for different programs onto different frequency channels. Because of these differences, the techniques used to distribute programs in a wireline broadcast network are generally not applicable for a wireless broadcast network.
There is therefore a need in the art for a wireless broadcast network that can efficiently broadcast different types of content with different coverage areas.